Vacuum cleaner with automatic nozzle height adjustment



Dec. 26, 1950 A. w. SEYFRIED 2,535,322

VACUUM CLEANER WITH AUTOMATIC NOZZLE HEIGHT ADJUSTMENT Filed Sept. 12, 1946 3 SheetsrSheet 1 Dec. 26, 1950 A. w. $EYFRIED VACUUM WITH- AUTOMATIC NOZZLE HEIGHT ADJUSTMENT 5". Sheets-Sheet 3 Filed. Sept 12,- 1946 Ss MK N Patented Dec. 26, 195.0

VACUUM CLEANER WITH AUTOMATI NOZZLE HEIGHT ADJUSTMENT Arthur William Scyfried, Racine, Wis., assitnor to Scovlll Manufacturing Company, Waterbury, Comp, a corporation of Connecticut Application September 12, 1948, Serial No. 698,429

7 Claims. 1

This invention relates to vacuum cleaners and particularly to a portable cleaner provided with a tiltably mounted, counterbalanced motor and nozzle unit in which the nozzle automatically adjusts itself relatively to the surfaces to be cleaned, and functions eiliciently for cleaning bare floors, as well as surfaces covered by thin and thick carpets.

The construction herein shown and described embodies certain features of the vacuum cleaner construction disclosed in United States Letters Patent No. 2,291,250, as well as other novel structures not shown therein. As stated in said patent, it is desirable to provide means for counterbalancing the weight of the handle in its various operative positions to overcome the tendency of the nozzle to be raised from the surface to be cleaned when the handle, carrying the dust bag, is moved rearwardly and lowered to allow the cleaner to move under furniture, and therefore the cleaner shown herein provides means for automatically maintaining the nozzle in proper operative position, regardless of the position of the handle, and improved counterbalancing means are provided in the cleaner for the purpose stated.

The cleaner shown automatically meets the requirements presented by a wide variety of types of surfaces to be operated upon, by the provision of a motor and nozzle unit pivotally mounted on a transverse axis, the weight of the unit rearwardly of the pivotal mounting exceeding the weight forwardly thereof, together with the provision of yielding counterbalancing means tending to urge the forward portion of the nozzle toward the surface to be cleaned but without permitting excessive sink of the nozzle.

Special means are provided for automatically and efficiently controlling the relative sink of the wheels which support the heaviest portion of the unit, namely, the motor and housing, and thereby control the position of the nozzle relatively to the surfaces to be cleaned. The said special means herein disclosed insure the proper positioning of the nozzle relatively to the surfaces to be cleaned to a much more accurate degree than has been possible heretofore.

In the drawings: A

Fig. 1 is a side elevation of a vacuum cleaner embodying my invention.

Fig. 2 is a plan view, partly in section, taken in the plane of the line 2-2 of Fig. 1.

Fig. 3 is a bottom view of the cleaner.

Fig. 4 is a plan view of part of the motor and nozzle unit supporting means, shown partly in i 2 section, the section being taken in the plane of the line 4-4 of Fig. 5.

Figs. 5 and 6 are longitudinal, vertical sectlonal views, showing the rear wheel carrying bracket positions when operating on a hard surface and on a soft surface, respectively.

Figs. 7, 8 and 9 are diagrammatic views showing the nozzle mouth, front and rear wheels as they appear when the cleaner is operating on a bare floor, a thin carpet and a thick carpet with pad, respectively.

In that embodiment of the invention shown in the drawings, the cleaner comprises a motor housing i0, fan housing II, and nozzle l2, cast or assembled into a unit. A handle I3 is mounted on the cleaner by means of a fork H which is fixed on the horizontal shaft l5, which preferably has square ends for that purpose. Nuts on the ends of the shaft are indicated at 16, The motor housing has lugs i1 cast thereon for supporting the shaft l5 beneath it. On the fork I4 is a slidable clip l8, slotted at l9, said slot being engaged by the pin or stud 20. When the handle I3 is moved downwardly and rearwardly, a stop member 2| on the housing engages the clip l8 and holds the handle in fixed position relatively to the cleaner body. In its upward position, the clip l8 clears the stop 2| and allows the handle to be moved downwardly.

The dust bag 22 is secured detachably to the handle I 3 and to the nozzle l2 in a conventional manner. The brush 23 is rotatably mounted in the nozzle i2 adjacent the mouth of the nozzle and the removable shield 24 partially closes the mouth of the nozzle and aids the nozzle in gliding over the surface to be cleaned.

The nozzle i2 is formed to receive the brush 23, in its forward portion, and is provided with rearward extensions at each side, and these are indicated at 25, 25. They house the wide tread front wheels 26, 26, mounted on the offset ends 21 of the shaft 28. The wheels 26 are rotatable on the said shaft 28 which is fixedly mounted in the supports 29, 29.

An adJusting screw 30 is provided for fixing the position of the mouth of the nozzle i2 relatively to the tread of the wheels 26, 26, in the manufacturing processes of adjusting the parts. In the bare floor adjustment, with the cleaner as a whole resting on the floor, the mouth of the nozzle I2 is designed to be .100 inch above the floor, as shown in Fig. 7. The relative positions ,of the nozzle will be referred to later in the description of the operation of the cleaner.

The means for supporting the cleaner in its rearward portion is an important feature of my invention. A bracket comprising a fiat portion 3| and downturned flanges 32 at each side is fixedly secured to the lower side of the motor housing l0. Another bracket or wheel-carrying member 33 is pivotally mounted between the flanges 32 of the fixed bracket 3| by means of a shaft 34. This pivotally mounted member 33 carries a narrow tread wheel 35 rotatably mounted on a shaft 36, and a wider tread wheel 31 rotatably mounted on the shaft 38. When the cleaner is standing on a bare fioor, the wheel-carrying member 33 is spaced from the fixed bracket 3|, 32, to its fullest extent. This is accomplished by the spring controlled plate 39 which is retained at its rearward end by the tongue 40 on the bracket 33 and on its forward end by being pivotally mounted on the shaft i5. A spring 4| coiled on the shaft l5, has an end 42 bearing on said plate 39. This arrangement holds the plate 39 under spring pressure against the fixed bracket 3| and the pivotally mounted bracket 33 in such way that it bears downwardly on the tongue 40 (Fig. 3) and tends normally to counterbalance the weight of the motor housing end of the body and to urge the mouth of the nozzle toward the surface to be "cleaned. As stated, the coiled spring 4| has its free end bearing against the upper surface of the plate 39; its other end is fixed to the shaft l5 by the screw 43.

It will be noted from Figs. 3 and 4, thatthe narrow tread rear wheel 35 is located forwardly of the wider tread rear wheel 31. Fig. 5 shows that the shafts 36 and 38 on which these rear wheels 35, 31, respectively, are mounted, are disposed in one horizontal plane when the cleaner is standing on a hard surface such as a bare floor. Fig. 6 shows that the shaft 36 which carries the narrow tread wheel 35 is disposed in a horizontal pane below that of the shaft 36 which carres the wider tread wheel 31, this being the relative positions of the shafts and wheels resulting from the sinking of the wheel 35 when the cleaner is operating on a thick or padded carpet.

The degree of sink of the narrow tread wheel 35 re atively to the wider wheel 31 determines the degree of support afforded by the wheel 31 in carrving the cleaner weight. This is illustrated in the diagrammatic views. Figs. '7, 8 and 9. In the first of these figures, the ceaner as a who e is supported by the front wheels 26 and equa ly by the whee s 35, 31 which rest on a hard surface in one horizontal plane. In Fig. 8, where the cleaner is operating on a thinly carpeted surface, some of the wei ht previously borne by the wheel 35 has been shifted to the wheel 31' due to the sink of the narrow wheel 35. In Fig. 9, still more of the wei ht has been shifted to the wheel 31 due to t e still greater sink of the narrow wheel 35 into the thickly carpeted surface on which the cleaner is operating.

The front wheels 26 are wide tread wheels designed to resist sinking, and designed to support the cleaner nozzle in proper relation to the surface to be cleaned. The axis of the parts 21 of shaft 28 on which these whee's are mounted is the transverse pivot about which the cleaner as a whole tilts. As indicated in Fig. 7, the distance between this transverse pivot and the center of the nozzle is 2.625 inches, and the distance from said center of the nozzle to the center between the rear wheels 35 and 31 is 8.1875 inches. Thus the rear wheels are more than three times as far from the center of the nozzle as are the front wheels 26. With the axis of the wheels 26 serving 4 as a fulcrum, very slight relative movement of the wheels 35, 31 is required to alter the position of the nozzle relatively to the surface to be cleaned, and to maintain it in its most eillcient operative position depending on the character of the said surface.

Extended experiments have proven that a cleaner designed to have its nozzle spaced from a bare floor .100 inch and from a carpeted floor approximately .060-.082 inch is most emcient. The cleaner of the present invention automotically functions to establish the optimum nozzle efilciency. Fig. 7 shows the nozzle .100 inch above the bare fioor, with wheels 35 and 31 resting on the floor in one horizontal plane. Fig. 8 shows the nozzle .062 inch at its center above a thinly carpeted surface, with the wheel 35 .085 inch beneath the surface and the wheel 3'! .070 inch beneath the surface at the lowermost portions of their treads. The wide wheel 26 sinks to a lesser degree, .045 inch. Fig. 9 shows the nozzle .060 inch at its center above a thickly carpeted surface, with the wheel 35 .275 inch beneath the surface and the wheel 31 .235 inch beneath the surface at the lowermost portions of their treads. The front wheels 26 have sunk .120 inch.

Figs. 8 and 9 thus illustrate the automatic functioning of the rear wheels 36, 31, to provide a variable fulcrum for the rear wheel carrying bracket 33 through which support is transmitted to the rearward portion of the cleaner body. By fulcrum I mean the point on the bracket 33 at which the resultant of the upward forces on axles 36 and 38 acts. When the cleaner is placed on rugs of increasing depths of nap, this fulcrum point is shifted rearwardly. This is due to the fact that the wheel 35, of greater sink capacity than the wheel 31, exerts its greater sinking capacity on thick soft rugs and thus permits the rearmost wheel 31 to bear weight to a greater extent than it does when the cleaner is placed on thin or very firm rugs. The rearward shifting of the fulcrum results in compressing the spring II and rotating the bracket 33 counter-clockwise. It is the relationship between the tread surfaces of the rear wheels 35, 31, which controls their relative sink on carpeted surfaces, and it is the relat ve positions of said rear wheel carrying bracket 33 and the front wheels 26 which control the position of the nozzle l2 relatively to the surface to be cleaned. These parts shift their relative horizontal-plane positions according to the surfaces on which they rest, and thereby automatically tilt the nozzle about the axis of the wheels 26 and adjust it to its designed operative position. The distance, longitudina ly of. the cleaner, between the center of the nozzle and the axis of the wheels 26 is fixed, but the distance between the center of the nozzel and the effective fulcrum of the bracket 33 varies according to the positions of the wheels 35 and 37. As heretofore explained, the posit ons of said wheels 35 and 3'! varies on account of their different sink capacity in different types of floor coverings.

Added to the influence of said wheels 26, 35 and 31 in determining the position of the nozzle relatively to the fioor, is the fact that lowering of the handle l3 tends to increase its leverage weight and to increase the pressure of the spring "-42 against the plate 39. These influences combine in determining the automatic adjustment of the nozzle to the surfaces to be cleaned.

' It will be understood that when the handle i3 is in its vertical position as shown in Fig. 1, its

front wheels 23 about which the cleaner as a whole pivots, but when the handle is moved rearwardly and downwardly, it exerts leverage added to weight, and this, in the absence of the spring "-42 bearing on plate 39, would tend to lift the forward end of the nozzle. The spring 41-42 urges the plate 39 and the wheel carrying bracket 33 .away from the motor casing and thus raises the motor casing relatively to the surface on which the device is standing, thereby counterbalancing the weight of the rearward end of the unit in increasing degrees as the handle is lowered and its leverage weight is increased. The variable fulcrum or point on bracket 33 produced by the wheels 35, 31 of different sink capacities is also affected by the leverage weight of the handle, said fulcrum moving rearwardly between the pivotal points 36 and 38, as the handle is moved downwardly and rearwardly. This action is brought into play when the cleaner is used under low furniture and the handle is moved radically downwardly. Without this counterbalancing means the forward edge of the nozzle would be raised unduly under the operating conditions described. The variable fulcrum provided by the bracket 33 cooperates with the counterbalanclng means under said operating conditions to maintain the nozzle in proper relation to the surface to be cleaned.

The measurements of spaces between nozzle and surface and of the sink of wheels which appear in Figs. '7, 8 and 9 were made on the forward stroke of the cleaner, with the handle 13 at a 45 angle.

The yieldingly mounted bracket 33 not only serves to carry the wheels 35 and 31 in their special relationship, but'the said bracket, wheels and the spring pressed plate 39 as assembled and mounted under the motor I0, serve to counterbalance the weight of the cleaner and the leverage weight of the handle rearwardlv .of the pivotal mounting of the wheels 25 on which the cleaner tilts to control the position of the nozzle.

Changes may be made in details of construction and in the form of the parts without departing from the scope of my invention as set forth in the appended claims.

I claim:

1. A vacuum cleaner comprising a motor and nozzle unit, means extending transversely between the nozzle and the center of weight of the cleaner pivotally supportingthe motor and nozzle unit, and means yieldingly connected to the rearward portion of the cleaner for supporting said portion and for automatically adjusting the position of the nozzle relatively to the surface to be cleaned, said means comprising a pivotally mounted bracket, a plurality of rotatable members of different tread areas mounted on the bracket and spaced apart longitudinally of the cleaner, the member of greater trea'd area bein rearmost, a biasing member pivotally mounted on the motor and nozzle unit and having its free end bearing on the pivotally mounted bracket, and resilient means bearing on the biasing member, whereby the rearward supporting means is resiliently urged downwardly, said resilient means being of such strength that the bracket will yield upwardly against said biasing means as the effective fulcrum of the rearward supporting means is shifted rearwardly due to variations in the relative degrees of sink of said rotatable members. i

2. A vacuum cleaner comprising a motor and nozzle unit, a pair of wheels mounted on an axis extending transversely of the cleaner between the nozzle and the center of weight of the cleaner pivotally supporting the motor and nozzle unit, and means yieldingly connected to the rearward portion of the cleaner for supporting said portion and for automatically adjusting the position of the nozzle relatively to the surface to be cleaned, said means comprising a pivotally mounted bracket, a plurality of rotatable members of different tread areas mounted on the bracket and spaced apart longitudinally of the cleaner, the member of greater tread area being rearmost, a biasing member pivotally mounted on the motor and nozzle unit and having its free end bearing on the pivotally mounted bracket, and resilient means bearing on the biasing member, whereby the rearward supporting means is resiliently urged downwardly, said resilient means being of such strength that the bracket will yield upwardly against said biasin means as the effective fulcrum of the rearward supporting means is shifted rearwardly due to variations in the relative degrees of sink of said rotatable members.

3. The vacuum cleaner defined by claim 1, in which the distance between the center of the nozzle and the variable fulcrum of the bracket is approximately three times the distance from the center of the nozzle to said transverse supporting means for the motor and nozzle unit.

4. The vacuum cleaner defined by claim 1, in which the transversely extending means for pivotally supporting the motor and nozzle unit comprise a pair of wheels having greater tread area than the combined tread area of said longitudinally spaced rotatable members on the bracket supporting the rearward portion of the cleaner.

5. A vacuum cleaner comprising a motor and nozzle unit, a shaft pivotally mounted on said unit, a handle fixed on said shaft, means extending transversely between the nozzle and the center of weight of the cleaner pivotally supporting the motor and nozzle unit, said unit being heavier rearwardly of said pivotal supporting means than forwardly thereof, and means yieldingly connected to the rearward portion of the cleaner for supporting said portion and for automatically adjusting the position of the nozzle relatively to the surface to be cleaned. said means comprising a pivotally mounted bracket, a plurality of rotatable members of different tread areas mounted on the bracket and spaced apart longitudinally of the cleaner, the member of greater tread area being rearmost, a biasing member on the shaft having its free end in engagement with the pivotally mounted bracket, and resilient means on the shaft bearing on the biasing member, whereby the rearward supporting means is resiliently urged downwardly and a lifting force is exerted on the handle to move it about its pivot to upright position and the weight of the unit and handle is counterbalanced in its different operative positions, said resilient means being of such strength that the bracket will yield upwardly against said biasing means as the effective fulcrum of the rearward supporting means is shifted rearward, due to variations in the relative degrees of sink of said rotatable members.

6. The vacuum cleaner defined by claim 5 in which the distance between the center of the nozzle and the variable fulcrum of the bracket is approximately three times the distance from the center of the nozzle to said transverse supporting means for the motor and nozzle unit.

I. The vacuum cleaner defined by claim 5 in which the transversehr extending means for pivotally supporting the motor and nozzle unit comprise a pair of wheels having greater tread area than the combined tread area 01' said longitudinally spaced rotatable members on the bracket supporting the rearward portion of the cleaner.

ARTHUR WILLIAM SEYFRIE).

REFERENCES crrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number Name Date Sparklin Sept. 29, 1936 Becker June 4, 1940 Taylor July 30, 1940 Taylor June 3, 1941 Taylor Dec. 30, 1941 Sparklin Apr; 21, 1942 Nielsen July 28, 1942 FOREIGN PATENTS Country Date Great Britain Jan. 29, 1941 

